Fatigue crack growth and life assessment of main landing gear rib trunnion in a special aircraft

Crack growth and fatigue life assessment of aviation parts are very important. One of the special and important parts in airplane is the Rib trunnion landing gear, which has been investigated in this research. Due to technological and material problems in I.R. Iran, H13 have been selected instead of HY-TUF material, and diameter of one holes for jointing to landing gear is increased 7 mm greater than the original one. According to these changes, life estimation of manufactured part becomes significant. For this reason, the behavior of fatigue crack growth to obtain the critical crack length, and the trajectory of the crack growth has been analysed. Finally, the fatigue life of the part has been assessed using fracture mechanics-based method considering an arbitrary initial crack. The results showed that the critical crack length for original and manufactured parts is 19.4 and 9.2 mm, respectively. The allowable initial crack length is 6 and 2 mm for the original and the manufactured parts, respectively.